Also posted in my build-up page.
After over 40,000 miles, the rubber bushings that came with the King rear shocks developed surface cracks and needed replacement. I was able to find some polyurethane Hyper-Flex bushings from Engergy Suspension. These are universal shock eye bushings, PN 9.8145R (they also come in black). The original rubber bushings are 1.88"OD x .75" thick and the new Hyper-Flex are 1.88" OD x .94" thick. The Hyper-Flex have a .56" ID so I removed the Teflon sleeves for the King rubber bushings. Total cost is less than $7 for all four new bushings. The rear swaybar was disconnected at the frame mount in order for the rear axle to droop down far enough to remove and replace the bushings.
Comparison of rubber and Hyper-Flex bushing (shown with rear shock bushing cap, flat washer, and 1/2-13 Nylok nut)
New bottom Hyper-Flex bushing installed with bushing nipple facing into frame mount (top bushing installed with nipple facing down into frame mount)
New Hyper-Flex bushings installed
These Hyper-Flex bushings should be more durable than rubber ones as they are more impervious to oil and other contaminants.